Monoceros: Wikis


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From Wikipedia, the free encyclopedia

List of stars in Monoceros
Abbreviation Mon
Genitive Monocerotis
Pronunciation /məˈnɒsɨrəs/, genitive /ˌmɒnəsɨˈroʊtɨs/
Symbolism the Unicorn
Right ascension 7.15 h
Declination −5.74°
Family Orion
Quadrant NQ2
Area 482 sq. deg. (35th)
Main stars 4
Stars with
known planets
Stars brighter than 3m 0
Stars within 10 pc (32.6 ly) 2
Brightest star β Mon A (3.76m)
Nearest star Luyten's Star
(12.37 ly, 3.79 pc)
Messier objects 1
Meteor showers December Monocerids
Alpha Monocerids
Canis Major
Canis Minor
Visible at latitudes between +75° and −85°.
Best visible at 21:00 (9 p.m.) during the month of February.

Monoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its creation is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east. Other bordering constellations include Canis Minor, Lepus and Puppis.


Notable features



Monoceros is a constellation that is not very easily seen with the naked eye, with only a few fourth magnitude stars. Alpha Monocerotis has a visual magnitude of 3.93, slightly brighter than Gamma Monocerotis, which has a visual magnitude of 3.98.

However, Monoceros does have some interesting features to observe with the aid of a small telescope. Beta Monocerotis is an impressive triple star system, the three stars forming a triangle which seems to be fixed. The visual magnitudes of the stars are 4.7, 5.2 and 6.1. William Herschel discovered it in 1781 and commented that it is "one of the most beautiful sights in the heavens".

Epsilon Monocerotis is a fixed binary, with visual magnitudes of 4.5 and 6.5.

S Monocerotis, or 15 Monocerotis, is a bluish white variable star and is located at the center of NGC 2264. However, the variation of its magnitude is not too great. It has a companion star of visual magnitude 8.

V838 Monocerotis had an outburst starting on January 6, 2002.

Monoceros also contains Plaskett's Star, which is a massive binary system whose combined mass is estimated to be that of almost 100 Suns put together.


Monoceros contains two super-Earth exoplanets in one planetary system: COROT-7b was detected by COROT satellite and COROT-7c was detected by radial velocity method from ground-based telescopes. COROT-7b has the smallest known radius of any known exoplanets: 1.7 Earth radii. Both planets in this system were discovered in 2009.

Deep sky objects

Monoceros contains many clusters and nebulae, most notable among them;


Monoceros is a relatively modern constellation. Its first certain appearance is on a globe created by the Dutch cartographer Petrus Plancius in 1612 or 1613[1], and was later charted by Jakob Bartsch as Unicornus in his star chart of 1624.

Heinrich Wilhelm Olbers and Ludwig Ideler[2] indicate (according to Richard Hinkley Allen's allegations) that the constellation may be older, quoting an astrological work [3] from 1564 that mentioned "the second horse between the Twins and the Crab has many stars, but not very bright"; these references may ultimately be due to Michael Scot of the 13th century, but refer to a horse and not a unicorn, and its position does not quite match. Joseph Scaliger is reported [4] to have found Monoceros on an ancient Persian sphere.


  1. ^ Le costellazioni di Petrus Plancius on
  2. ^ Ideler, Ludwig (1809). Untersuchungen über den Ursprung und die Bedeutung der Sternnamen: Ein Beytrag zur Geschichte des gestirnten Himmels. Berlin. pp. 354..355.   freely available HERE
  3. ^ Himmels Lauffs Wirkung und natürliche Influenz der Planeten Gestirne und Zeichen aufs Grund der Astronomie. Frankfurt. 1564.  
  4. ^ Allen, Richard Hinckley (1899). Star Names - their lore and meaning, online link. Dover. p. 290.  


  • Ridpath, Ian; Wil Tirion (2007). Stars and Planets Guide. London: Collins. ISBN 978-0-00-725120-9. Princeton: Princeton University Press. ISBN 978-0691135564.  

External links

Coordinates: Sky map 07h 09m 00s, −05° 44′ 24″


Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also monoceros



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First recorded by the astronomer Jakob Bartsch in 1624, but possibly created earlier by Petrus Plancius. From Latin monoceros, a "unicorn"

Proper noun




  1. (astronomy) A winter constellation of the northern sky, said to resemble a unicorn. It lies amid the Milky Way, just east of the constellation Orion.

Derived terms



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